Made from Carbon steel, high hardness, rustproof, which is sturdy and . Locking Knob Plunger can control the expansion and contraction of the pin by adjusting the handle, so as to achieve the effect of indexing, positioning or stop limit. Indexing plunger with spring, smooth rotation, and , long service life. Indexing plungers, when in use, pull the handle out and it 90 degrees and release. Achieve precise indexing and positioning with our Knob Plunger. Perfect for enthusiasts and alike.